Security forces set up roadblocks and snipers took up positions on government buildings in the Indian capital Thursday to prevent possible militant attacks ahead of national day celebrations, officials said.
Authorities sealed off much of downtown New Delhi, through which a parade _ the highlight of the Jan. 26 Republic Day festivities _ passes every year.
Officials announced that the city's metro rail service would be partially shut down for several hours Friday.
Russia's President Vladimir Putin, set to arrive Thursday for a two-day visit, was to be the chief guest at Friday's parade.
At least 15,000 police and paramilitary soldiers have been deployed around the city, a top police official, Dipendra Pathak, said Wednesday.
"All Delhi police personnel will be involved in the massive security and policing arrangements in the capital," Pathak said.
Although there have been no specific threats, a spate of deadly terror attacks in 2006 _ from the bombings of a temple in the Hindu holy city of Varanasi to the Mumbai railway bombings that killed more than 200 people _ warranted the extra security, he said.
Also, several separatist groups in the country's restive northeast and in the Indian-controlled part of Kashmir have called general strikes for Republic Day.
Republic Day marks the adoption of India's democratic constitution in 1950. The country gained freedom from British colonial rule in 1947.
Police have stepped up security around the capital's showpiece new metro rail network, which officials fear could be a target for rebel groups.
Metro services will be suspended on part of the network for nearly seven hours on Friday, said Anuj Dayal, a spokesman for Delhi Metro Rail Corporation.